my_list = [1, 3, 4, 5, 6]
print(my_list[:4]) #步长默认是一

my_tuple = (1, 2, 3, 4, 5)
print(my_tuple[:]) #起始和结束不写表示从头到尾，步长为1可以省略

my_str = "0123456789"
print(my_str[::2])

print(my_str[::-1])
print(my_list[3:1:-1])
print(my_tuple[::-2])

my_s = "yllis si txx"
print(my_s[::-1][4:6])
print(my_s.split(" ")[1][::-1])


l = []

print(not l)